// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_VIEWS_DELEGATE_H_
#define UI_VIEWS_VIEWS_DELEGATE_H_

#include <string>

#if defined(OS_WIN)
#include <windows.h>
#endif

#include "base/callback.h"
#include "base/location.h"
#include "base/macros.h"
#include "base/strings/string16.h"
#include "build/build_config.h"
#include "ui/accessibility/ax_enums.h"
#include "ui/base/ui_base_types.h"
#include "ui/gfx/native_widget_types.h"
#include "ui/views/views_export.h"
#include "ui/views/widget/widget.h"

namespace base {
class TaskRunner;
class TimeDelta;
}

namespace content {
class WebContents;
class BrowserContext;
class SiteInstance;
}

namespace gfx {
class ImageSkia;
class Rect;
}

namespace ui {
class ContextFactory;
}

namespace views {

class NativeWidget;
class NonClientFrameView;
class ViewsTouchEditingControllerFactory;
class View;
class Widget;

#if defined(USE_AURA)
class TouchSelectionMenuRunnerViews;
#endif

namespace internal {
    class NativeWidgetDelegate;
}

// ViewsDelegate is an interface implemented by an object using the views
// framework. It is used to obtain various high level application utilities
// and perform some actions such as window placement saving.
//
// The embedding app must set the ViewsDelegate instance by instantiating an
// implementation of ViewsDelegate (the constructor will set the instance).
class VIEWS_EXPORT ViewsDelegate {
public:
    using NativeWidgetFactory = base::Callback<NativeWidget*(const Widget::InitParams&,
        internal::NativeWidgetDelegate*)>;
#if defined(OS_WIN)
    enum AppbarAutohideEdge {
        EDGE_TOP = 1 << 0,
        EDGE_LEFT = 1 << 1,
        EDGE_BOTTOM = 1 << 2,
        EDGE_RIGHT = 1 << 3,
    };
#endif

    enum class ProcessMenuAcceleratorResult {
        // The accelerator was handled while the menu was showing. No further action
        // is needed and the menu should be kept open.
        LEAVE_MENU_OPEN,

        // The accelerator was not handled. Menu should be closed and the
        // accelerator will be reposted to be handled after the menu closes.
        CLOSE_MENU
    };

    virtual ~ViewsDelegate();

    // Returns the ViewsDelegate instance if there is one, or nullptr otherwise.
    static ViewsDelegate* GetInstance();

    // Call this method to set a factory callback that will be used to construct
    // NativeWidget implementations overriding the platform defaults.
    void set_native_widget_factory(NativeWidgetFactory factory)
    {
        native_widget_factory_ = factory;
    }
    const NativeWidgetFactory& native_widget_factory()
    {
        return native_widget_factory_;
    }

    // Saves the position, size and "show" state for the window with the
    // specified name.
    virtual void SaveWindowPlacement(const Widget* widget,
        const std::string& window_name,
        const gfx::Rect& bounds,
        ui::WindowShowState show_state);

    // Retrieves the saved position and size and "show" state for the window with
    // the specified name.
    virtual bool GetSavedWindowPlacement(const Widget* widget,
        const std::string& window_name,
        gfx::Rect* bounds,
        ui::WindowShowState* show_state) const;

    virtual void NotifyAccessibilityEvent(View* view, ui::AXEvent event_type);

    // For accessibility, notify the delegate that a menu item was focused
    // so that alternate feedback (speech / magnified text) can be provided.
    virtual void NotifyMenuItemFocused(const base::string16& menu_name,
        const base::string16& menu_item_name,
        int item_index,
        int item_count,
        bool has_submenu);

    // If |accelerator| can be processed while a menu is showing, it will be
    // processed now and LEAVE_MENU_OPEN is returned. Otherwise, |accelerator|
    // will be reposted for processing later after the menu closes and CLOSE_MENU
    // will be returned.
    virtual ProcessMenuAcceleratorResult ProcessAcceleratorWhileMenuShowing(
        const ui::Accelerator& accelerator);

#if defined(OS_WIN)
    // Retrieves the default window icon to use for windows if none is specified.
    virtual HICON GetDefaultWindowIcon() const;
    // Retrieves the small window icon to use for windows if none is specified.
    virtual HICON GetSmallWindowIcon() const = 0;
    // Returns true if the window passed in is in the Windows 8 metro
    // environment.
    virtual bool IsWindowInMetro(gfx::NativeWindow window) const;
#elif defined(OS_LINUX) && !defined(OS_CHROMEOS)
    virtual gfx::ImageSkia* GetDefaultWindowIcon() const;
#endif

    // Creates a default NonClientFrameView to be used for windows that don't
    // specify their own. If this function returns NULL, the
    // views::CustomFrameView type will be used.
    virtual NonClientFrameView* CreateDefaultNonClientFrameView(Widget* widget);

    // AddRef/ReleaseRef are invoked while a menu is visible. They are used to
    // ensure we don't attempt to exit while a menu is showing.
    virtual void AddRef();
    virtual void ReleaseRef();

    // Creates a web contents. This will return NULL unless overriden.
    virtual content::WebContents* CreateWebContents(
        content::BrowserContext* browser_context,
        content::SiteInstance* site_instance);

    // Gives the platform a chance to modify the properties of a Widget.
    virtual void OnBeforeWidgetInit(Widget::InitParams* params,
        internal::NativeWidgetDelegate* delegate)
        = 0;

    // Returns the default obscured text reveal duration.
    virtual base::TimeDelta GetDefaultTextfieldObscuredRevealDuration();

    // Returns true if the operating system's window manager will always provide a
    // title bar with caption buttons (ignoring the setting to
    // |remove_standard_frame| in InitParams). If |maximized|, this applies to
    // maximized windows; otherwise to restored windows.
    virtual bool WindowManagerProvidesTitleBar(bool maximized);

    // Returns the context factory for new windows.
    virtual ui::ContextFactory* GetContextFactory();

    // Returns the user-visible name of the application.
    virtual std::string GetApplicationName();

#if defined(OS_WIN)
    // Starts a query for the appbar autohide edges of the specified monitor and
    // returns the current value.  If the query finds the edges have changed from
    // the current value, |callback| is subsequently invoked.  If the edges have
    // not changed, |callback| is never run.
    //
    // The return value is a bitmask of AppbarAutohideEdge.
    virtual int GetAppbarAutohideEdges(HMONITOR monitor,
        const base::Closure& callback);
#endif

    // Returns a blocking pool task runner given a TaskRunnerType.
    virtual scoped_refptr<base::TaskRunner> GetBlockingPoolTaskRunner();

protected:
    ViewsDelegate();

private:
    scoped_ptr<ViewsTouchEditingControllerFactory> views_tsc_factory_;

#if defined(USE_AURA)
    scoped_ptr<TouchSelectionMenuRunnerViews> touch_selection_menu_runner_;
#endif

    NativeWidgetFactory native_widget_factory_;

    DISALLOW_COPY_AND_ASSIGN(ViewsDelegate);
};

} // namespace views

#endif // UI_VIEWS_VIEWS_DELEGATE_H_
